I have been keeping my RAW files as well as Dng files. A friend just told me that I should delete the Raw files as soon as I make the Dng files. Do most folks do this? I just went to Mac from Win and now find that when I upload photos from my camera, Bridge now asks if I want to change the Raw to Dng. Sounds like a good idea. any suggestions or comments?
Robert

If your converting to DNG than I would say yes delete them, the only reason to convert to DNG now as far as I'm concerned is to save disk space so it makes no sense to save them both. BTW I don't convert to DNG.

I import my RAW files as dng and don't save any RAW fies anymore. For all of my purposes the dng holds all of the information that I need. Now saving is not as much about space but more about controlling the number of versions on the same file. The same reason that since I switched from PS to LR I almost never create a tiff file any longer.

No need for both. The benefits of Raw vs DNG are still open to debate. As mentioned above DNG MAY be longer lived and RAW MAY be safer. Most people are sticking with RAW for now. Flip a coin and pick one

I've been using a DNG workflow ever since the format was introduced in late 2004 but I still keep ALL my Raw files.

Raw conversion tools are improving all the while and its beneficial to revisit past conversions/edits with the new tools. If the Raw files were discarded then I couldn't take advantage of improvements in software like DxO Optics Pro and Canon's DPP.

Second, there have been errors in the DNG converters in the past, although that's less likely to happen now with public betas. I recall both ACR/DNG 4.3 and 4.4 were withdrawn by Adobe because of bugs in the conversion process. If I had simply converted to DNG and deleted the Raw files I would be stuck with faulty conversions.

mhayes5254 wrote:
Converting to DNG should have no impact on the use of new raw tools. Both contain the uninterpreted raw sensor data. A new convertor should be able to read both. That is the whole point of DNG.

Hmmm....I guess "should" is the operative word but as with many other things that isn't always the case. For example, while DXO Optics Pro can output DNG files it will not recognize DNG files generated by Adobe DNG/ACR/Lightroom. So if you converted Raw to DNG and discarded the raw files, you wouldn't be able to process them in an alternative raw converter like DxO.

Also, outside of Adobe software very few programs can read and interpret the DNG format. Neither Canon's Digital Photo Pro nor Nikon's Capture NX 2 can process DNG files. So if you discard your raw files then want to use the manufacturer's software you'd be out of luck.

Now this isn't a problem if you have a strictly Adobe workflow but if you occasionally use alternative Raw converters it makes sense to keep the Raw files.

Given how inexpensive disk space is these days, it makes no sense to me to delete my original RAW files. At $80 for a 2TB drive, that works out to roughly 1/10 of a cent per RAW file. Even using redundant mirrored RAID arrays for storage it woks out to under one cent per file, even including the offline backup copies.

James,
Very interesting info. Since I was not yet convinced of the claimed benefits of DNG, I have not invested much effort into the details. Based on your info, my conclusion is that DNG is complely useless at the moment and should be avoided at all costs.

If DxO cannot read DNG, it seems highly irresponsible for them to call their files DNG

Have DNG as your working file and RAW as your backups. Correct me if I'm wrong - you can convert to DNG from Raw, but not the other way around. Also, from what I've read the xmp file hangs with or is part of the DNG file, where with Raw it sits along side of the it.

mhayes5254 wrote:
James,
Very interesting info. Since I was not yet convinced of the claimed benefits of DNG, I have not invested much effort into the details. Based on your info, my conclusion is that DNG is complely useless at the moment and should be avoided at all costs.

If DxO cannot read DNG, it seems highly irresponsible for them to call their files DNG

I suppose some clarification is in order. DxO Optics Pro creates linear DNG files i.e. the file is demosaiced and all three channels are calculated as they would be in a 16-bit TIFF. Linear DNG files can be edited in any image processing software. On the other hand, the DNG files created by ACR/Lightroom/DNG Converter are non-linear and are not demosaiced so the file remains a combination of 12- or 14-bit sensor data and metadata. DxO Optics Pro cannot read this Color FIlter Array (CFA) DNG.

DNG is certainly not "useless." My catalog consists of images shot with several camera brands and models. The DNG format makes then consistent so I never have to worry if my Raw converter can handle a particular Raw file format.

Methodical wrote:
Have DNG as your working file and RAW as your backups. Correct me if I'm wrong - you can convert to DNG from Raw, but not the other way around. Also, from what I've read the xmp file hangs with or is part of the DNG file, where with Raw it sits along side of the it.

Al

That's exactly how I do it. After downloading all my Raw files, I cull them and rename; then convert them to DNG. The Raw files are archived and the DNGs go either into my Lightroom catalog or to Bridge for "one off" processing where I don't want to catalog them in Lightroom.

For the images where I might want to use the manufacturer's software I have the Raw files to use there.

The editing metadata for DNG files is written to the file header instead of XMP sidecar files with Raw files. Also, DNG automatically updates the embedded preview to reflect the editing changes; Raw previews cannot be updated so they would only be viewable in the application that initially edited them.

For my current needs, managing various versions is far more complexity than I am interested in. I process the RAW files with LR and output what I need to PS, print, etc. The risk here is that it assumes that the LR library will be available forever. The XMP files can be written to disk but this also assumes some Adobe program will be available forever to use the info. Obviously neither of these assumptions are true.

When I am done processing a set, I export finished JPG's to the source folder. Basically this is to cover the worst case scenario where the source RAW files are not readable in the future. Although I would not be able to reprocess, I will at least have a usable image that is not dependent on any processing software. Perhaps the direction of RAW vs DNG will become clearer in the future. I have family prints that are more than 120 year old. No software needed to view them. What current file format has the best probability of beating that?